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authorChris Metcalf <cmetcalf@tilera.com>2012-03-15 13:13:38 -0400
committerChris Metcalf <cmetcalf@tilera.com>2012-03-15 13:13:38 -0400
commit48b25c43e6eebb6c0edf72935e8720385beca76b (patch)
treed1c774a79ef5a8373b093479c3dabe9bf16aec07 /arch/s390
parentfde7d9049e55ab85a390be7f415d74c9f62dd0f9 (diff)
[PATCH v3] ipc: provide generic compat versions of IPC syscalls
When using the "compat" APIs, architectures will generally want to be able to make direct syscalls to msgsnd(), shmctl(), etc., and in the kernel we would want them to be handled directly by compat_sys_xxx() functions, as is true for other compat syscalls. However, for historical reasons, several of the existing compat IPC syscalls do not do this. semctl() expects a pointer to the fourth argument, instead of the fourth argument itself. msgsnd(), msgrcv() and shmat() expect arguments in different order. This change adds an ARCH_WANT_OLD_COMPAT_IPC config option that can be set to preserve this behavior for ports that use it (x86, sparc, powerpc, s390, and mips). No actual semantics are changed for those architectures, and there is only a minimal amount of code refactoring in ipc/compat.c. Newer architectures like tile (and perhaps future architectures such as arm64 and unicore64) should not select this option, and thus can avoid having any IPC-specific code at all in their architecture-specific compat layer. In the same vein, if this option is not selected, IPC_64 mode is assumed, since that's what the <asm-generic> headers expect. The workaround code in "tile" for msgsnd() and msgrcv() is removed with this change; it also fixes the bug that shmat() and semctl() were not being properly handled. Reviewed-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/Kconfig1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 6d99a5fcc090..0ff53e350092 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -218,6 +218,7 @@ config COMPAT
prompt "Kernel support for 31 bit emulation"
depends on 64BIT
select COMPAT_BINFMT_ELF
+ select ARCH_WANT_OLD_COMPAT_IPC
help
Select this option if you want to enable your system kernel to
handle system-calls from ELF binaries for 31 bit ESA. This option